Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the ... [more ▼]

Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the planet without resorting to freezing. Other the type of packaging and the storage temperature, the shelf-life of meat is directly related to its initial microbiological ecosystem and its evolution. Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or genera of bacteria. In this way, the presence of certain lactic acid bacteria adapted to a low temperature in fresh meat could extend the shelf life and improve the microbial stability and safety of this product. The aim of this study was to perform a morphological and functional characterization of a C. maltaromaticum strain (lab. ref. CFAUS2/DLC/4/E1) with potential bioprotective effect isolated from commercial vacuum packaged long shelf life beef. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. Morphological, biochemical and enzymatic profiles of the isolated C. maltaromaticum strain were similar to those of two reference strains (LMG 11393 and LMG 22902). The evaluation of the influence of different atmospheres showed that the growth of C. maltaromaticum was the slowest in an atmosphere containing 70 % O2 and 30 % CO2. Vacuum packaging is therefore more suitable for the growth of this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat. The functional characterization of this strain will be further pursued by genotypic characterization and its potential bioprotective effect will also be studied. [less ▲]

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining ... [more ▼]

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining the stunning and the sticking in one single step. The main difference lies in the fact that, in the halal protocol, a single cut with a sharp knife is practiced directly on live cattle, instead of two cutting steps with two different knives for the sticking in the classical slaughtering technique. The unique section in the halal technique results generally in the cross section of trachea and esophagus of cattle. The aim of this study was to seek if the two slaughtering techniques were similar regarding the superficial contamination of carcasses, swabbed between 2 and 4 hours after the killing step. For this purpose, classical microbiological tests (TVC and Enterobacteriaceae) and 16S rDNA metagenetic analysis were carried out from 20 cattle carcasses (swabbing of “legal” zone – 1.600 cm2 – and in the neck area – 200 cm2). The classical microbiological results revealed no significant differences between the two slaughtering practices. Statistical analysis of pyrosequencing data showed that differences in bacterial population abundance between slaughtering methods were mainly found in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to Actinobacteria (Brevibacterium, Corynebacterium) were more aundant in “Halal” samples whereas populations from the Proteobacteria (Caulobacteraceae, Comamonadaceae, Bradyrhizobiaceae) and Firmicutes (Lactobacillus) were more abundand in the “classical” group. The analysis of OTU abundance of bacteria from the digestive or respiratory tract revealed no differences beteween groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis to the genus level underlines differences between methods, the legal swabbing zone being still the best sampling zone compared to the neckline. The next step will be the identification of precise contamination origin of the differences found between slaughtering methods. [less ▲]

Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI). Therefore, hospitalized patients are considered particularly vulnerable to CDI. The main objective of this study was to evaluate the prevalence of C. difficile in a Spanish hospital and to characterize the isolates with respect to the PCR-ribotype, antibiotic resistance and toxin activity. In addition, multilocus sequence typing (MLST) was performed in order to study clonal relationships between C. difficile isolates obtained from two different countries. Culture of samples was performed in a selective medium cycloserine cefoxitin fructose cholate. An identification of the isolated colonies was done by PCR detection of tpi, tcdA, tcdB and cdtA genes. Toxic activity was confirmed by a cytotoxic immunoassay. Further characterization was performed by PCR ribotyping. MLST was used in order to determine genetic relationships between Spanish and Belgian C. difficile isolates recovered from hospital patients in both countries. C. difficile was frequently detected in hospitalized patients. The isolates belonged to different PCR ribotypes, including type 027. Most of the strains obtained harboured tcdA and tcdB genes. The number of positive faecal samples considerably increased among elderly patients over 65 years old. The multi-locus sequence typing (MLST) analysis showed that some Spanish and Belgian isolates cluster in the same lineage. This study reveals the circulation of toxigenic C. difficile in a Spanish hospital. The relatedness between Belgian and Spanish isolates indicate a common source or a lack of diversity from some PCR-ribotypes. Moreover, data obtained suggest that the combination of ribotyping and MLST is a good tool for the inter-laboratory comparison of strains among different countries. Continuous inter-country surveillance is suitable to understand the spread of C. difficile isolates among hospitalized patients. [less ▲]

Introduction: Clostridium difficile is a spore-forming pathogen considered as a major cause of enteric disease in humans, with faecal-oral route as the primary mode of transmission. However, recent ... [more ▼]

Introduction: Clostridium difficile is a spore-forming pathogen considered as a major cause of enteric disease in humans, with faecal-oral route as the primary mode of transmission. However, recent studies have reported the occurrence of C. difficile in ground meats at retail stores, indicating that foods could be an additional source of infection in the community. Purpose: The objective of this study was to determine the resistance of C. difficile spores in contaminated ground meat during cooking process. Methods: Prior to testing, to obtain spores and to enhance heterogeneity, spores of two different strains were produced in two nutritious broths. C. difficile spores were experimentally inoculated in 45 g of ground meat (beef and pork) in order to obtain a final contamination of 4,500 ufc g-1. Six heating temperatures (70, 75, 80, 85, 90 and 95°C) were chosen. Samples were heating in a water bath with an integrated program for time-temperature. One sample without inoculum was used as control with a temperature probe placed inside. Once the desired temperature was research in the core of the sample, the heat treatment was prolonged for 10 min. Subsequently, all the samples were placed on the chilling room (4°C) before analyse. These experiments were conducted in duplicate with a spore enumeration in triplicate. Results: Heating contaminated ground meat at 70, 75 and 80°C for 10 min was not effective for C. difficile spores inhibition. However, 10 min of heat shock at 80°C was the only temperature that significantly reduced the number of countable colonies. Heat treatment at 85°C (or more) inhibits the germination of both of the strains tested. Significance: Ensure that ground meat, like burgers or sausages, is heated to more than 85°C would be an important measure to reduce the risk of C. difficile food transmission. [less ▲]

Increasing age, several co-morbidities, environmental contamination, antibiotic exposure and other intestinal perturbations appear to be the greatest risk factors for C. difficile infection (CDI). Therefore, elderly care home residents are considered particularly vulnerable to CDI. The main objective of this study was to evaluate and follow the prevalence of C. difficile in a Belgian nursing home. During a 4-month period, stool samples from a group of 23 elderly care home residents were collected weekly. A C. difficile microbiological detection scheme was performed along with an overall microbial biodiversity study of the faeces content by Targeted Metagenomic analysis. Culture of samples was performed in a selective medium cycloserine cefoxitin fructose cholate. An identification of the isolated colonies was done by PCR detection of tpi, tcdA, tcdB and cdtA genes. Toxic activity was confirmed by a cytotoxic immunoassay. Further characterization was performed by PCR ribotyping. The Metagenomic analysis was targeted on the v1-v3 hyper-variable region of 16S rDNA. The taxonomical assignment of the populations was performed with MOTHUR and Blast algorithms. Seven out of 23 (30.4%) residents were (at least one week) positive for C. difficile. The most common PCR-ribotype identified was 027. Targeted Metagenomic analyses reveals that each resident has his own bacterial imprint, which is stable during the entire study. Residents’ positives for C. difficile by classical microbiology showed an important proportion of C. difficile sequences. However, Metagenomics analysis can’t substitute targeted protocols. It was not used as a diagnostic tool to detect C. difficile but rather to determine the identification and correlations of the major bacterial populations that are present in the gut microbiota. In conclusion, this unique association of classical microbiology protocol with pyrosequencing allowed to follow C. difficile in patients and to identify several other bacterial populations whose abundance is correlated with C. difficile. [less ▲]

Agricultural practices have a strong impact on soil bacterial and fungal community composition. Furthermore, microbial community composition can change with the stage of plant development. We are ... [more ▼]

Agricultural practices have a strong impact on soil bacterial and fungal community composition. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture (conventional and reduced tillage) and plant stage (germination and flowering) in soil conditions. Here, instead of examining this impact at a high taxonomic level such as phylum and/or class, thus missing potentially relevant information from lower levels, we propose an original method: exploiting the available sequence information at the lowest taxonomic level attainable for each operational taxonomic unit. Results show that some microbial communities were impacted only by the tillage practice , while others were impacted only by the stage of plant. Changes in microbial community composition could be due to the soil conditions induced by the soil practice and the stage of plant. [less ▲]

Soil microorganisms such as mycorrhizae and plant-growth-promoting rhizobacteria have beneficial effects on crop productivity. Agricultural practices are known to impact soil microbial communities, but ... [more ▼]

Soil microorganisms such as mycorrhizae and plant-growth-promoting rhizobacteria have beneficial effects on crop productivity. Agricultural practices are known to impact soil microbial communities, but past studies examining this impact have focused mostly on one or two taxonomic levels, such as phylum and class, thus missing potentially relevant information from lower levels. Therefore we propose here an original, sub-phylum method for studying how agricultural practices modify microbial communities. This method involves exploiting the available sequence information at the lowest taxonomic level attainable for each operational taxonomic unit. In order to validate this novel method we assessed microbial community composition using 454 pyrosequencing of 16S and 28S rRNA genes, then we compared the results with results of a phylum-level analysis. Agricultural practices included conventional tillage, reduced tillage, residue removal and residue retention. Results show that, at the lowest taxonomic level attainable, tillage is the main factor influencing both bacterial community composition, accounting for 13% of the variation, and fungal community composition, accounting for 18% of the variation. Whereas phylum-level analysis failed to reveal any effect of soil practice on bacterial community composition, and missed the fact that different members of the same phylum responded differently to tillage practice. For instance, the fungal phylum Chytridiomycota showed no impact of soil treatment, while sub-phylum-level analysis revealed an impact of tillage practice on the Chytridiomycota sub-groups Gibberella, which includes a notorious wheat pathogen, and Trichocomaceae. This clearly demonstrates the necessity of exploiting the information obtainable at sub-phylum level when assessing the effects of agricultural practice on microbial communities. [less ▲]

This study investigates the contamination of foods and surfaces with Clostridium difficile in a single nursing home. C. difficile PCR-ribotype 078 was found in one food sample and in none of the tested ... [more ▼]

This study investigates the contamination of foods and surfaces with Clostridium difficile in a single nursing home. C. difficile PCR-ribotype 078 was found in one food sample and in none of the tested surfaces. These results indicate that food and surfaces are an unlikely source of C. difficile infection in this setting. [less ▲]

Objective: Triggered by the growing knowledge on the link between the intestinal microbiome and human health, the interest in probiotics is ever increasing. The authors aimed to review the recent ... [more ▼]

Objective: Triggered by the growing knowledge on the link between the intestinal microbiome and human health, the interest in probiotics is ever increasing. The authors aimed to review the recent literature on probiotics, from definitions to clinical benefits, with emphasis on children. Sources: Relevant literature from searches of PubMed, CINAHL, and recent consensus statements were reviewed. Summary of the findings: While a balanced microbiome is related to health, an imbalanced microbiome or dysbiosis is related to many health problems both within the gastro-intestinal tract, such as diarrhea and inflammatory bowel disease, and outside the gastro-intestinal tract such as obesity and allergy. In this context, a strict regulation of probiotics with health claims is urgent, because the vast majority of these products are commercialized as food (supplements), claiming health benefits that are often not substantiated with clinically relevant evidence. The major indications of probiotics are in the area of the prevention and treatment of gastrointestinal related disorders, but more data has become available on extra-intestinal indications. At least two published randomized controlled trials with the commercialized probiotic product in the claimed indication are a minimal condition before a claim can be sustained. Today, Lactobacillus rhamnosus GG and Saccharomyces boulardii are the best-studied strains. Although adverse effects have sporadically been reported, these probiotics can be considered as safe. Conclusions: Although regulation is improving, more stringent definitions are still required. Evidence of clinical benefit is accumulating, although still missing in many areas. Misuse and use of products that have not been validated constitute potential drawbacks. [less ▲]

Multilocus sequence typing (MLST), multilocus variable-number tandem-repeat analysis (MLVA) and antimicrobial susceptibility were performed on 37 animal and human C. difficile isolates belonging to 15 different PCR-ribotypes in order to investigate the relatedness of human and animal isolates and to identify possible transmission routes. MLVA identified a total of 21 different types while MLST only distinguished 12 types. Identical C. difficile strains were detected in the same animal species for PCR-ribotypes 014, 078, UCL 16U and UCL 36, irrespective of their origin or the isolation date. Non clonal strains were found among different hosts; however, a high genetic association between pig and cattle isolates belonging to PCR-ribotype 078 was revealed. MLVA also showed genetic differences that clearly distinguished human from animal strains. For a given PCR-ribotype, human and animal strains presented a similar susceptibility to the antimicrobials tested. All strains were susceptible to vancomycin, metronidazole, chloramphenicol and rifampicin, while PCR-ribotypes 078, UCL 5a, UCL 36 and UCL 103 were associated with erythromycin resistance. The data suggest a wide dissemination of clones at hospitals and breeding-farms or a contamination at the slaughterhouse, but less probability of interspecies transmission. However, further highly discriminatory genotyping methods are necessary to elucidate interspecies and zoonotic transmission of C. difficile. [less ▲]

Clostridium difficile remains the leading cause of healthcare-associated diarrhoea and outbreaks continue to occur worldwide. Aside from nosocomial C. difficile infection, the bacterium is also ... [more ▼]

Clostridium difficile remains the leading cause of healthcare-associated diarrhoea and outbreaks continue to occur worldwide. Aside from nosocomial C. difficile infection, the bacterium is also increasingly important as a community pathogen. Furthermore, asymptomatic carriage of C. difficile in neonates, adults and animals is also well recognised. The investigation of the gut's microbial communities, in both healthy subjects and patients suffering C. difficile infection (CDI), provides findings and information relevant for developing new successful approaches for its treatment, such as faecal microbiota transplantation, or for the prophylaxis of the infection by modification of the gut microbiota using functional foods and beverages. The analysis of all available data shows new insights into the role of intestinal microbiota in health and disease. [less ▲]

Microbiota in the gastro-intestinal tract are closely related to both the intestinal and overall health of the host. Experimental chickens have always been euthanized in order to identify and quantify the ... [more ▼]

Microbiota in the gastro-intestinal tract are closely related to both the intestinal and overall health of the host. Experimental chickens have always been euthanized in order to identify and quantify the bacteria in cecal content. In this study, quantification and identification of the microbial populations in cecal drop, cecal content and fecal drop samples from chickens showed that cecal drop contains a bacterial community that is very similar (concerning bacterial diversity, richness and species composition) to cecal content, as opposed to the bacterial community found in fecal drop. Cecal drop analysis thus allows for longitudinal experiments on chickens' cecal bacteria. The varying results in the analysis of fecal samples questions the method's reliability in reflecting the true cecal microbiota in chickens. [less ▲]